Relay



Dec. 25 1923. 1,478,547

V. BROWN ET AL RELAY Filed July 12 .1920

jade/12am 7651 2010 fiTOw/V (Jase 0h -E Patented Dec. 25, 19 23.

UNITED STATES PATENT OFFICE.

VERNON BROWN AND JOSEPH E. PENGILLY. L08 ANGELIS, CALIFORNIA.

nanny.

Application filed July 12, 1920. Serial No. 395,612.

To all'whom it may concern Be it known that we, VERNON BROWN and Josnrrr H. PENGILLY, both citizens of the United States, residing at Los Angeles, county of Los Angele's, andState of California, have invented a new and useful Improvement Comprising the Relay described in-the following specification.

Our invention relates to relays which are commonly connected into an electric circuit for the purpose of accomplishing certain results upon the occurrence of predetermined conditions within that circuit. It more particularly relates to what is known as the overload relay, these relays being inserted in a circuit to accomplish certain results upon the occurrence of overload or excessive current conditions in that circuit. 7

The particular embodiment of overload relay shown and described is one which is adapted to be usedin'connection with the no voltage coil of a circuit breaker. Circuit breakers provided with no voltage coils are common in the art, the no-voltage coil bein connected to the circuit to be protected and being mechanically so arranged that the cirguit breaker opens whenever the voltage alls.

Our invention comprises a relay which is adapted to open the circuit to the no voltage coil in the event that excessive current is imposed upon this circuit to be protected, the

no-voltage coil opening the circuit breaker as soon as its circuit is interrupted.

Our invention further comprises a relay which is so arranged that the opening of the circuit of the no voltage coil does not occur unt l the overload condition has persisted for a certain length of time, the exact interval depending upon the severity of the v overload and the adjustment of the relay.

A further object of the invention 1s to provide a relay which can be adjusted for various overload conditions and which will be also so constructed that it can be readily inspected, repaired and adjusted.

Further objects and advantages will be made evident hereinafter.

Referring to the drawings which are for illustration only,

Fig. 1 is an elevation partly in section of our invention and Fig. 2 is a plan view in setion on a plane represented by the line 22 of Fig.

The embodiment of the invention shown is provided with two overload coils 12 car-- ried in a magnetic circuit 13. Insulating tubes 14 project up inside the magnetic circuit 13 and inside the coils 12, an armature or plunger 15 being provided in each of the tubes 14. The tubes 14 are .provided with enlarged heads 16 and with an annular groove 17 on their lower edge. Dash ots 18 also formed of insulating material t into the groove 17 being held tightly in place by means of a lower bar 19, which is forced upwardly by a thumb nut 100 on a screw 20 forcing the dash pots 18 against the heads 16 and forcing the heads 16 against an upper bar 21 which is held by means of a set screw 22 on the screw 20. The screw 20 is calibrated as shown at 23 being secured by means of a screw 24 in the lower cross bar of the supporting frame 13. Extending across the bottom of each of the dash pots 18 is a partition 30 dividing the lower portion of the dash pot into two spaces in which are placed pools of mercury. Metal members 32 secured in the head 16 project into these pools and are connected by means of wires 33 and 34 with each other or with an external circuit which will hereinafter be described.

Secured to the armatures 15 by rods 40 are pistons 41, these pistons fitting fairly tight in the dash pots 18 and having perforations through which the rods 32 pa$. Fitting loosely in the pistons 41 are bridging members 50, these bridging members being formed of metal and of the shape shown in Fig. 1. Two bridging members 50 are provided in each of the dash pots 18, these members normally resting on the bottom of the dash pot and connecting the pools of mercury 31 to ether. 4

' The method of operation is as follows:

The coils 12 are connected into the cir cuit to be protected. This may be a single phase circuit in which case one of these coils may be connected into either wire of that circuit or it may be a three phase circuit in which the coils 12 are each connected into one phase of that circuit. The Wires 33 are connected in series with the circuit and with the no voltage coil on the circuit breaker, this coil not being shown ing members 50 connecting the pools of mercury 81, the wire 34 connecting two oi the dash pots in serieswith each other. Upon the occurrence of an overload in the circuit one or both of the armatures 15 1s pulled upwardly. The space above the pool of mercury is tilled with an insulating liquid preferably a mineral oil. Immediately upon the establishment of a pull on one of the pistons 41 through the rod 40 from the armature 15 a partial vacuum is lormedbelow the piston 41, the pressure of the air upon the top of this piston resisting the pull of the armature 15. This partialvacuum is slowly relieved by the flow of oil around the periphery and through the holes in the piston 41 so that the piston moves upward slowly under the influence of this pull. During ment, the bridging tionary sliding tree members 50 remain stain the piston 41 until this piston reaches a certain position which is determined by the shape of the bridging members 50. e/"Vhen the piston reaches this position it starts to lift the members 50 gradually raising them out of the pools of mercury and opening the circuit between the wires 33 and 34. As soon as this circuit is opened, the no voltage coil of the breaker operates andopens the circuit breaker thus disconnecting the circuit to be protected from the source of power. This (lo-energizes the coils 12 and the armatures 15 iallunder the influence of gravity re-establishing the circuit so that. when the circuit breaker is again thrown in, the no-voltage coil will be energized. If it is desired to change the calibration so that the armatures l5 operate upon a higher or lower current, the set screw is released and the dash pots 18 together with the bars 19 and 21 are moved up and down by turning the thumb nut 100 on the screw 20, thus moving the whole assembly up or down on the screw 20. When the proper calibration is reached the set screw 20 is forced into place. It is then possible to remove the thumb nut 100 and the bar 19 and to take off the dash pots18 for inspection, cleaning or refilling. The dash pots can then be replaced without disturbing the calibration in any way.

Our invention has a peculiar utility in connection with induction motors. These motors are commonly provided with a novoltage release circu1t breaker and our invention is designed to protectsuch motors against excessive current. Such motors, however, require comparatively heavy currents to start. These starting currents being of brief duration, it is possible by the use of our device to rotect against continued overloads and at t e same time to allow the motor to draw a heavy current during the starting period without tripping the circuit breaker.

two pools. insulated "from each the early part of this moveaerator We claim as our invention.

1. A contact -malring device comprising: a head; a dash pot-removably secured to said head; electrically conducting liquid in the lower end of aid dash pot; an insulating partition dividing said body of liquid into other; two conducting members each secured in said head, one of said members making-electrical contact with one of said pools, and the other of said'members making electrical contact with the other of said pools; a conducting bridging member normally having one end making electrical contact with "one of said pools, the other end simultaneously making electrical contact with the other of said pools; and means for moving said bridging member upwardly to break contact with said pools.

2. A contact making device comprising: a head; a dash pot removably secured to said head; electrically conducting liquid in the lower end of said dash pot; an insulating partition dividing said body of liquid into two pools insulated from each other; two conducting members each secured in said head, one of said members making electrical contact with one of said pools, and the other of said members making electrical cohtact with the other of said pools; a conducting bridging member normally having one end making electrical contact with one of said pools, the other end simultaneously making electrical contactlwith the other of said pools; a piston sliding in said dash pot, sai'l conducting members projecting through said piston; and means by which said piston moves said bridging member upwardly to break contact with said pools.

3. A contact making device comprising: a head; a dash pot removably secured-to said head; electrically conducting liquid in the lower end of said dash pot; an insulating partition dividing said body of liquid into two pools insulated from each other; two conducting members each secured in said head, one of said members making electrical contact with one of said pools, and the other of said members making electrical contact with the other of said pools; a conducting bridging member normally having one end making electrical contact with one of said pools, the other end simultaneously making electrical contact with the other of said pools; a piston sliding in said dash pot, said conducting members projecting through said piston, said bridgin member being carried by said piston; an means for moving said bridging member upwardly to break contact with said ools.

In testimony whereof, we have hereunto set our hands at Los Angeles, QalifOrnia, this 1st day of June, 1920.

' VERNON BROWN.

JUSEPH PENGILLY. 

